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1 | #include <stdio.h> | |
2 | #include "fakeasm.h" | |
3 | typedef unsigned char u8; | |
4 | ||
5 | u8 zero; //r16 | |
6 | u8 acc; //r17 | |
7 | u8 i0; //r18 | |
8 | u8 i1; //r19 | |
9 | u8 i2; //r20 | |
10 | u8 i3; //r21 | |
11 | u8 n; //r22 | |
12 | u8 s; //r23 | |
13 | u8 _; //r24 | |
14 | //r25 | |
15 | u8 x;/*==Ml*/ //r26 (Xlo) | |
16 | u8 t;/*==Mh*/ //r27 (Xhi) | |
17 | //r28 | |
18 | //r29 | |
19 | void *Z; //r30 (Zlo) | |
20 | /*...*/ //r31 (Zhi) | |
21 | #define Mh x //mod3 vars | |
22 | #define Ml t // -"- | |
23 | ||
24 | // .section .data | |
25 | u8 data[] = { | |
26 | /*.byte*/ 0x84, 0x9d, 0xb0, 0x69, 0x9d, 0x84, 0x69, 0x58, | |
27 | /*.byte*/ 0x75, 0x8c, 0xb0, 0x69, 0x8c, 0x75, 0x69, 0x58 | |
28 | }; | |
29 | ||
30 | // .section .text | |
31 | ||
32 | //http://homepage.divms.uiowa.edu/~jones/bcd/mod.shtml | |
33 | void mod3(void) { | |
34 | // mod3(Mh.Ml) -> t | |
35 | #define tmp _ | |
36 | ADD (Ml, Mh) | |
37 | CLR (Mh) | |
38 | ADC (Mh, zero, carry) //Mh only holds the carry bit | |
39 | MOV (tmp, Ml) | |
40 | SWAP (tmp) | |
41 | ANDI (tmp, 0x0f) | |
42 | SWAP (Mh) | |
43 | OR (tmp, Mh) | |
44 | ANDI (Ml, 0x0f) | |
45 | ADD (Ml, tmp) | |
46 | MOV (tmp, Ml) | |
47 | LSR (tmp) | |
48 | LSR (tmp) | |
49 | ANDI (Ml, 0x03) | |
50 | ADD (Ml, tmp) | |
51 | MOV (tmp, Ml) | |
52 | LSR (tmp) | |
53 | LSR (tmp) | |
54 | ANDI (Ml, 0x03) | |
55 | ADD (Ml, tmp) | |
56 | CPI (Ml, 3) | |
57 | BRPL (skip) | |
58 | SUBI (Ml, 3) | |
59 | skip:; | |
60 | RET | |
61 | #undef tmp | |
62 | } | |
63 | //.macro definitions for mul-tree: | |
64 | #define always(_bit) //nop; for when a test() is not necessary (see tree) | |
65 | #define never(_bit) //nop; for when a test() is not necessary (see tree) | |
66 | #define test(_bit,_jmpto) \ | |
67 | SBRC (t, _bit) \ | |
68 | RJMP (_jmpto) | |
69 | #define shift16 \ | |
70 | LSR (a2) \ | |
71 | ROR (a1) | |
72 | #define shift8 /*top three bits don't need to be corrrect, so save cycles by not carrying*/ \ | |
73 | LSR (a1) | |
74 | #define shift0 //nop; last shift is common | |
75 | #define add_shift16 \ | |
76 | ADD (a1, i0) \ | |
77 | ADC (a2, i1, carry) \ | |
78 | shift16 | |
79 | #define add_shift8 /*ditto with carrying*/ \ | |
80 | ADD (a1, i0) \ | |
81 | shift8 | |
82 | #define add_shift0 /*last shift is common*/ \ | |
83 | ADD (a1, i0) | |
84 | void g(void) { | |
85 | // g(i, t) -> t | |
86 | // tempvars: `x` and `_` | |
87 | #define tmp _ | |
88 | ANDI (t, 0x07) | |
89 | MOV (tmp, i2) | |
90 | ANDI (tmp, 3) | |
91 | TST (tmp) | |
92 | CPSE (tmp, zero) | |
93 | SUBI (t, -8) | |
94 | #undef tmp | |
95 | ||
96 | #define tmp _ | |
97 | MOV (tmp, t) //NOTE: must move value away from `t`, as that is also hi(X) | |
98 | tmp = data[tmp];/* | |
99 | LDI Xhi, hi8(data) | |
100 | LDI Xlo, lo8(data) | |
101 | ADD Xlo, tmp ;<-- the offset (formerly `t`) into data[] | |
102 | ADC Xhi, zero | |
103 | LD tmp, X */ | |
104 | MOV (t, tmp) | |
105 | #undef tmp | |
106 | ||
107 | #define a1 x | |
108 | #define a2 _ | |
109 | #define a0 t | |
110 | CLR (a2) | |
111 | CLR (a1) | |
112 | ||
113 | /* decision tree multiplication saves cycles and (hopefully) reduces code size | |
114 | _xxx? | |
115 | / \ | |
116 | _xx?0 _xx1? | |
117 | | | | |
118 | _x?00 _x?01 | |
119 | / \ / \ | |
120 | _?000 _?100 _?001 _?101 | |
121 | / \ / \ | / \ | |
122 | _0000 _1000 _0100 _1100 _1001 _0101 _1101 | |
123 | | | | | | | | | |
124 | ... ... ... ... ... ... ... | |
125 | | | | | | | | | |
126 | B0 58 84 8C 69 75 9D */ | |
127 | test (0, m____1) | |
128 | m____0: shift16 | |
129 | never (1) | |
130 | m___00: shift16 | |
131 | test (2, m__100) | |
132 | m__000: shift16 | |
133 | test (3, m_1000) | |
134 | m_0000: shift16 | |
135 | always (4) | |
136 | add_shift16 | |
137 | always (5) | |
138 | add_shift8 | |
139 | never (6) | |
140 | shift8 | |
141 | always (7) | |
142 | add_shift0 | |
143 | RJMP (end_mul) // calc'd 0xb0 | |
144 | ||
145 | m_1000: add_shift16 | |
146 | always (4) | |
147 | add_shift16 | |
148 | never (5) | |
149 | shift8 | |
150 | always (6) | |
151 | add_shift8 | |
152 | never (7) | |
153 | shift0 | |
154 | RJMP (end_mul) // calc'd 0x58 | |
155 | ||
156 | m__100: add_shift16 | |
157 | test (3, m_1100) | |
158 | m_0100: shift16 | |
159 | RJMP (upper_8) //'ll calc 0x84 | |
160 | ||
161 | m_1100: add_shift16 | |
162 | upper_8: /* used twice, so deduplicated */ | |
163 | never (4) | |
164 | shift16 | |
165 | never (5) | |
166 | shift8 | |
167 | never (6) | |
168 | shift8 | |
169 | always (7) | |
170 | add_shift0 | |
171 | RJMP (end_mul) // calc'd 0x8c | |
172 | ||
173 | m____1: add_shift16 | |
174 | never (1) | |
175 | m___01: shift16 | |
176 | test (2, m__101) | |
177 | m__001: shift16 | |
178 | always (3) | |
179 | m_1001: add_shift16 | |
180 | never (4) | |
181 | shift16 | |
182 | always (5) | |
183 | add_shift8 | |
184 | always (6) | |
185 | add_shift8 | |
186 | never (7) | |
187 | shift0 | |
188 | RJMP (end_mul) // calc'd 0x69 | |
189 | ||
190 | m__101: add_shift16 | |
191 | test (3, m_1101) | |
192 | m_0101: shift16 | |
193 | always (4) | |
194 | add_shift16 | |
195 | always (5) | |
196 | add_shift8 | |
197 | always (6) | |
198 | add_shift8 | |
199 | never (7) | |
200 | shift0 | |
201 | RJMP (end_mul) // calc'd 0x75 | |
202 | ||
203 | m_1101: add_shift16 | |
204 | always (4) | |
205 | add_shift16 | |
206 | never (5) | |
207 | shift8 | |
208 | never (6) | |
209 | shift8 | |
210 | always (7) | |
211 | add_shift0 | |
212 | // calc'd 0x9d | |
213 | ||
214 | end_mul: | |
215 | LSR (a1) //final shift is a common operation for all | |
216 | ||
217 | MOV (t, a1) //TODO: use a1 in main() directly | |
218 | #undef a0 | |
219 | #undef a1 | |
220 | #undef a2 | |
221 | RET //TODO: replace CALL/RET with IJMP? (requires undoing goto-mul-hack) | |
222 | }; | |
223 | ||
224 | int main(void) { | |
225 | CLR (zero) | |
226 | CLR (i0) | |
227 | CLR (i1) | |
228 | CLR (i2) | |
229 | CLR (i3) | |
230 | for (;;) { | |
231 | MOV (n, i2) | |
232 | LSL (n) | |
233 | LSL (n) | |
234 | #define tmp _ | |
235 | MOV (tmp, i1) | |
236 | SWAP (tmp) | |
237 | ANDI (tmp, 0x0f) | |
238 | LSR (tmp) | |
239 | LSR (tmp) | |
240 | OR (n, tmp) | |
241 | #undef tmp | |
242 | MOV (s, i3) | |
243 | LSR (s) | |
244 | ROR (s) | |
245 | ANDI (s, 0x80) | |
246 | #define tmp _ | |
247 | MOV (tmp, i2) | |
248 | LSR (tmp) | |
249 | OR (s, tmp) | |
250 | #undef tmp | |
251 | ||
252 | //voice 1: | |
253 | MOV (t, n) | |
254 | RCALL g(); | |
255 | SWAP (t) | |
256 | ANDI (t, 1) | |
257 | MOV (acc, t) | |
258 | ||
259 | //voice 2: | |
260 | #define tmp _ | |
261 | MOV (tmp, i2) | |
262 | LSL (tmp) | |
263 | LSL (tmp) | |
264 | LSL (tmp) | |
265 | MOV (t, i1) | |
266 | SWAP (t) | |
267 | ANDI (t, 0xf) | |
268 | LSR (t) | |
269 | OR (t, tmp) | |
270 | #undef tmp | |
271 | EOR (t, n) | |
272 | RCALL g(); | |
273 | LSR (t) | |
274 | LSR (t) | |
275 | ANDI (t, 3) | |
276 | AND (t, s) | |
277 | ADD (acc, t) | |
278 | ||
279 | //voice 3: | |
280 | MOV (Ml, i2) | |
281 | SWAP (Ml) | |
282 | ANDI (Ml, 0xf0) | |
283 | LSL (Ml) | |
284 | #define tmp _ | |
285 | MOV (tmp, i1) | |
286 | LSR (tmp) | |
287 | LSR (tmp) | |
288 | LSR (tmp) | |
289 | OR (Ml, tmp) | |
290 | #undef tmp | |
291 | MOV (Mh, i3) | |
292 | SWAP (Mh) | |
293 | ANDI (Mh, 0xf0) | |
294 | LSL (Mh) | |
295 | #define tmp _ | |
296 | MOV (tmp, i2) | |
297 | LSR (tmp) | |
298 | LSR (tmp) | |
299 | LSR (tmp) | |
300 | OR (Mh, tmp) | |
301 | #undef tmp | |
302 | RCALL mod3(); | |
303 | ADD (t, n) | |
304 | RCALL g(); | |
305 | LSR (t) | |
306 | LSR (t) | |
307 | ANDI (t, 3) | |
308 | MOV (x, s) | |
309 | INC (x) | |
310 | #define tmp _ | |
311 | MOV (tmp, x) | |
312 | LSR (tmp) | |
313 | LSR (tmp) | |
314 | ADD (tmp, x) | |
315 | ROR (tmp) | |
316 | LSR (tmp) | |
317 | ADD (tmp, x) | |
318 | ROR (tmp) | |
319 | LSR (tmp) | |
320 | ADD (tmp, x) | |
321 | ROR (tmp) | |
322 | LSR (tmp) | |
323 | AND (t, tmp) | |
324 | #undef tmp | |
325 | ADD (acc, t) | |
326 | ||
327 | //voice 4: | |
328 | MOV (Ml, i2) | |
329 | SWAP (Ml) | |
330 | ANDI (Ml, 0xf0) | |
331 | LSL (Ml) | |
332 | LSL (Ml) | |
333 | #define tmp _ | |
334 | MOV (tmp, i1) | |
335 | LSR (tmp) | |
336 | LSR (tmp) | |
337 | OR (Ml, tmp) | |
338 | #undef tmp | |
339 | MOV (Mh, i3) | |
340 | SWAP (Mh) | |
341 | ANDI (Mh, 0xf0) | |
342 | LSL (Mh) | |
343 | LSL (Mh) | |
344 | #define tmp _ | |
345 | MOV (tmp, i2) | |
346 | LSR (tmp) | |
347 | LSR (tmp) | |
348 | OR (Mh, tmp) | |
349 | #undef tmp | |
350 | RCALL mod3(); | |
351 | SUB (t, n) | |
352 | NEG (t) | |
353 | SUBI (t, -8) | |
354 | RCALL g(); | |
355 | LSR (t) | |
356 | ANDI (t, 3) | |
357 | INC (s) | |
358 | #define tmp _ | |
359 | MOV (tmp, s) | |
360 | LSR (tmp) | |
361 | ADD (tmp, s) | |
362 | ROR (tmp) | |
363 | LSR (tmp) | |
364 | LSR (tmp) | |
365 | ADD (tmp, s) | |
366 | ROR (tmp) | |
367 | ADD (tmp, s) | |
368 | ROR (tmp) | |
369 | LSR (tmp) | |
370 | LSR (tmp) | |
371 | AND (t, tmp) | |
372 | #undef tmp | |
373 | ADD (acc, t) | |
374 | ||
375 | putchar(acc<<4); //TODO | |
376 | SUBI (i0, -1) | |
377 | ADC (i1, zero, !i0) //XXX: must use "sbci i1,-1" in the assembly version | |
378 | ADC (i2, zero, !i0&&!i1) // sbci i2,-1 | |
379 | ADC (i3, zero, !i0&&!i1&&!i2) // sbci i3,-1 | |
380 | } | |
381 | } |